Current ISO Standards Research Articles

Uncertainty evaluation of indentation modulus in the nano-range: Contact stiffness contribution

Evaluation of indentation modulus by instrumented indentation in the nano-range can use one of two methods for contact stiffness evaluation, according to current ISO standards. The relevance of contact stiffness, suggested by a preliminary uncertainty analysis, prompted development of improved evaluation procedures. Data on a series of indentation tests, performed in an international comparison on tungsten and fused silica with forces in the millinewton range, were analysed with standard methods, and two alternative ones. Uncertainty evaluation revealed some shortcomings in the standard methods concerning the estimation of contact stiffness and indentation modulus; some definite advantages are shown with improved procedures.

Standardized Loads Acting in Hip Implants.

With the increasing success of hip joint replacements, the average age of patients has decreased, patients have become more active and their expectations of the implant durability have risen. Thus, pre-clinical endurance tests on hip implants require defining realistic in vivo loads from younger and more active patients. These loads require simplifications to be applicable for simulator tests and numerical analyses. Here, the contact forces in the joint were measured with instrumented hip implants in ten subjects during nine of the most physically demanding and frequent activities of daily living. Typical levels and directions of average and high joint loads were extracted from the intra- and inter-individually widely varying individual data. These data can also be used to analyse bone remodelling at the implant-bone interface, evaluate tissue straining in finite element studies or validate analytical loading predictions, among other uses. The current ISO standards for endurance tests of implant stems and necks are based on historic analytical data from the 1970s. Comparisons of these test forces with in vivo loads unveiled that their unidirectional orientations deviate from the time-dependent in vivo directions during walking and most other activities. The ISO force for testing the stem is substantially too low while the ISO force for the neck better matches typical in vivo magnitudes. Because the magnitudes and orientations of peak forces substantially vary among the activities, load scenarios that reflect a collection of time-dependent high forces should be applied rather than using unidirectional forces. Based on data from ten patients, proposals for the most demanding activities, the time courses of the contact forces and the required cycle numbers for testing are given here. Friction moments in the joint were measured in addition to the contact forces. The moment data were also standardized and can be applied to wear tests of the implant. It was shown that friction only very slightly influences the stresses in the implant neck and shaft.

АНАЛІЗ ДОСВІДУ ГРУЗІЇ В ОРГАНІЗАЦІЇ ТА ВИДІЛЕННІ МІКРОЗОН ДЛЯ ВИРОБНИЦТВА ВИН КОНТРОЛЬОВАНИХ НАЙМЕНУВАНЬ ЗА ПОХОДЖЕННЯМ

The article contains the analysis of the modern state of the legislative framework of Georgia and its implementation concerning organization of controlled wine names of origin production in existing traditional appellations and methodological approaches for allocation and legislative recognition of new microzones for this category wines production. There is also a discussion of the possibility of use of Georgian experience in the process of formation of controlled wine names of origin wines domestic category. Special attention is paid to the organization of organoleptic estimation of Georgian wines that was one of the most important trends in the general process of the modern stage of sector reforming. The work of the Central state taste panel, just as the unit of analysis of physical and chemical parameters of wine quality and authenticity, is built upon the modern procedural framework according to the current ISO standards related to selection, training and attestation of tasters and working environment with compulsory observation of complete anonymity of samples without their discussion according to the two-stage five-mark grading system.

Recommendation for modifying current cytotoxicity testing standards for biodegradable magnesium-based materials

As one of the most promising medical metal implants, magnesium (Mg) or its alloys have shown significant advantages over other candidates attributed to not only their excellent biodegradability and suitable mechanical properties but also their osteopromotive effects for bone applications. Prior to approval mandated by the governmental regulatory body, the access to the medical market for Mg-based implants requires a series of testing for assurance of their safety and efficacy via preclinical evaluations and clinical tests including phase 1 and 2 evaluations, and phase 3 of multi-center randomized double blind and placebo-controlled clinical trials. However, as the most widely used protocols for biosafety evaluation of medical devices, current ISO 10993 standards should be carefully reevaluated when directly applying them to predict potential health risks of degradable Mg based biomaterials via cytotoxicity tests due to the huge gap between in vitro and in vivo conditions. Therefore, instead of a direct adoption, modification of current ISO standards for in vitro cytotoxicity test is desirable and justified. The differences in sensitivities of cells to in vitro and in vivo Mg ions and the capability of in vivo circulation system to dilute local degradation products were fully considered to propose modification of current ISO standards. This paper recommended a minimal 6 times to a maximal 10 times dilution of extracts for in vitro cytotoxicity test specified in ISO 10993 part 5 for pure Mg developed as potential orthopedic implants based on literature review and our specifically designed in vitro and in vivo tests presented in the study. Our work may contribute to the progress of biodegradable metals involved translational work.

Occupational Health Impacts of Climate Change: Current and Future ISO Standards for the Assessment of Heat Stress

The current system of International Standards (ISO) is assessed to consider whether standards are fit for purpose for the future in the context of climate change. ISO 7243, ISO 7933 and ISO 9886 provide the current ISO system for the assessment of heat stress. These involve a simple monitoring index, an analytical approach and physiological monitoring, respectively. The system relies on accurate measurement of the thermal conditions experienced by the worker (ISO 7726); and estimations of metabolic heat production due to work (ISO 8996) and the thermal properties of clothing (ISO 9920). As well as standards for heat stress assessment, the full range of ISO standards and the physical environment is listed as well as current work and proposed standards. A particular 'gap' in anticipating requirements for ISO standards in the future is the link between meteorological data and ISO standards. This is important for predicting the global consequences of a changing climate and anticipating potential impacts on occupational health across countries and cultures.

Computation of Tensile Strain-Hardening Exponents through the Power-Law Relationship

Abstract Many metals flow in the region of uniform plastic deformation following a power-law relationship, which states that true stress is proportional to true-plastic strain raised to the power n. The exponent n, known as the tensile strain-hardening exponent, can be determined from a tension test through appropriate transformations of stress-strain data and least-squares fitting of a straight line. Procedures for the computation of n have been standardized by ASTM International and ISO. Current ASTM and ISO standards differ, most notably, in the type of strain used in calculations. The ASTM procedure permits the use of true strain (true-elastic strain plus true-plastic strain), when true-elastic strain represents less than 10 % of total strain. On the other hand, the ISO version stipulates the subtraction of true-elastic strain from true strain, using a formula whose derivation is not publicly available. In this work, we revisit the expressions that enable the transformation of engineering stress-strain data to true-stress and true-plastic-strain values. Using eight tension-test curves from several materials, obtained through ASCII files publicly available at the website of the National Physical Laboratory of the United Kingdom, we compare n-values obtained via three definitions of strain: (i) true strain, (ii) conventional definition of true-plastic strain, and (iii) true-plastic strain according to the ISO formula. In addition, we investigate the dependency of the results on the strain range over which n-values are calculated. To evaluate strain-range dependency, which arises when metals do not closely follow the power-law relationship, we analyze the effect of strain intervals of increasing length and study the variation of n-values when the range of interest is divided into subintervals. To improve the approximation given by the power-law relationship over the region under analysis, we propose an alternative formulation in which the strength coefficient and the strain-hardening exponent are functions of true-plastic strain.

Reprint of: Improved cytotoxicity testing of magnesium materials

Metallic magnesium (Mg) and its alloys are highly suitable for medical applications as biocompatible and biodegradable implant materials. Magnesium has mechanical properties similar to bone, stimulates bone regeneration, is an essential non-toxic element for the human body and degrades completely within the body environment. In consequence, magnesium is a promising candidate as implant material for orthopaedic applications. Protocols using the guideline of current ISO standards should be carefully evaluated when applying them for the characterization of the cytotoxic potential of degradable magnesium materials. For as-cast material we recommend using 10 times more extraction medium than recommended by the ISO standards to obtain reasonable results for reliable cytotoxicity rankings of degradable materials in vitro . In addition primary isolated human osteoblasts or mesenchymal stem cells should be used to test magnesium materials.

Improved cytotoxicity testing of magnesium materials

Abstract Metallic magnesium (Mg) and its alloys are highly suitable for medical applications as biocompatible and biodegradable implant materials. Magnesium has mechanical properties similar to bone, stimulates bone regeneration, is an essential non-toxic element for the human body and degrades completely within the body environment. In consequence, magnesium is a promising candidate as implant material for orthopaedic applications. Protocols using the guideline of current ISO standards should be carefully evaluated when applying them for the characterization of the cytotoxic potential of degradable magnesium materials. For as-cast material we recommend using 10 times more extraction medium than recommended by the ISO standards to obtain reasonable results for reliable cytotoxicity rankings of degradable materials in vitro . In addition primary isolated human osteoblasts or mesenchymal stem cells should be used to test magnesium materials.

Progress in standardization of fretting fatigue terminology and testing

This paper reviews the current ASTM, ISO, and other standards that pertain in part to fretting fatigue and fretting wear testing. A historical perspective gives some background on why there still are relatively few standards for fretting fatigue and fretting wear testing. Current standards on the books tend to be application specific. In the past few years, there have been some new activities in standardization. These developments along with future needs in standardization are discussed.

Influence of Ageing and Contamination of Polymer Quenchants on Cooling Characteristics

The quenching operation is a critical part of the heat treatment process. The cooling characteristics of a quenchant will change during its working life. Improper quenching parameters and the drifting of the cooling characteristics can cause unforeseen costs if a malfunctioning component necessitates additional operations, e. g. straightening, machining, rework, or even rejection. For a polymer quenchant the cooling characteristics are influenced by, inter alia, concentration, agitation, temperature, thermal degradation, contamination and drag-out. In this study tests have been performed in order to study how the ageing and contamination of polymer quenchants influence the cooling characteristics. Polymers used for induction hardening in showers as well as in quench baths have been evaluated with regard to e.g cooling curves, refractive index and kinematic viscosity after ageing. Quenchants used in industrial applications have been evaluated. Cooling curves have been evaluated by using the ivf SmartQuench™ system. This is a tool for testing quenching media, primarily against the current ISO and ASTM standards for hardening oils and polymers. A large number of characteristics are recorded or calculated, such as cooling times to certain temperatures and cooling rates at these temperatures.

Spatial data modeling in the real estate cadastre using ISO 19100 series of standards

Introduction Standardization in geo-information technologies contributes to the establishment of efficient information functions, their greater stability and easier transition. Application of international, national and internal standards in the process of developing software products in the field of geo-information technology creates conditions for the development of efficient, low cost, reliable and secure software products. Spatial data modeling basics for real estate cadastre In terms of modeling, the spatial information of real estate cadastre is based on the vector data model which is suitable for modeling objects with a smaller number of properties with emphasis on the position. The vector spatial data model consists of two components: spatial and descriptive. The basis of the spatial one is geometry that contains metric data usually given in coordinates of a reference system. Geometry and Topology uniquely determine the shape, size and position of the object model in space, i.e. they represent its spatial component. Merging the spatial component with the descriptive one results in a completely defined object from the real world. Elements of spatial data quality Spatial data quality can be reviewed through a set of the following elements: origin, positional accuracy, attribute accuracy, completeness, logical consistency, semantic accuracy and the time information. The elements of spatial data quality listed above are provided using ISO 19100 series of standards. Application of ISO19100 series of standards in spatial data modeling for real estate cadastre Standards brought by the ISO organization have their wide application in the field of geographic information systems, including the cadastre and real estate, primarily in spatial data modeling. Cadastral systems must be generic and flexible to meet the demands that arise or change over time. Flexible information systems are one of the most important items of Driving Model Architecture (MDA). MDA is based on information systems models described in UML language. Other advantages of the MDA approach are especially prominent in today's highly variable IT environment. These advantages are portability, interoperability, platform independence. Series of ISO19100 standards are supporting the implementation of MDA. A model of a modern cadastre would be defined in accordance with current ISO standards and structured in a logically related components - document: business processes (UML Use Case Diagrams), UML Application Scheme, GML Schema Application, catalog of objects, metadata catalog, symbol catalog, coordinate system. ISO standards integration Components of the modern real estate cadastre model integrate several ISO standards simultaneously. A cadastral application scheme is a crucial component of the model data. The application Schema defines: data structure, attributes of object classes, specification of operations for manipulating and processing, conditions of integrity. The cadastral Application UML schema is an object-oriented conceptual scheme of the real estate cadastre, intended for implementation in modern geospatial databases. International Standard ISO 19109 defines rules for creating a consistent Application Scheme (including a consistent definition of object classes), for the purpose of collecting, processing, analyzing, accessing, presentation and distribution of spatial data. ISO 19109 standard for creating Application Schemes, relies on other standards from the ISO 19100 series, primarily in the 19103, 19107, 19108 and 19110. ISO 19103 standard specifies the use of Unified Modeling Language (UML) in geographic information modeling. ISO 19107 standard provides a conceptual scheme for describing and manipulating features of spatial objects. The standard operations for access, query, management, processing and sharing spatial data are defined during the modeling. Standardization in this area is the basis for other geographic standards. Conclusion Spatial data modeling is given greater importance. High costs of collecting and processing spatial data require special attention in all phases of design and implementation of geographic information systems. Therefore, it is necessary to comply with the current international ISO standards in modeling spatial data for real estate cadastre. The paper describes possibilities of application of relevant standards from ISO 19100 in modeling spatial data for real estate cadastre. .

Realistic loads for testing hip implants

The aim here was to define realistic load conditions for hip implants, based on in vivo contact force measurements, and to see whether current ISO standards indeed simulate real loads. The load scenarios obtained are based on in vivo hip contact forces measured in 4 patients during different activities and on activity records from 31 patients. The load scenarios can be adapted to various test purposes by applying average or high peak loads, high-impact activities or additional low-impact activities, and by simulating normal or very active patients. The most strenuous activities are walking (average peak forces 1800 N, high peak forces 3900 N), going up stairs (average peak forces 1900 N, high peak forces 4200 N) and stumbling (high peak forces 11,000 N). Torsional moments are 50% higher for going up stairs than for walking. Ten million loading cycles simulate an implantation time of 3.9 years in active patients. The in vitro fatigue properties of cementless implant fixations are exceeded during stumbling. At least for heavyweight and very active subjects, the real load conditions are more critical than those defined by the ISO standards for fatigue tests.

Voluntary GHG management using a life cycle approach. A case study

Voluntary GHG management is a primary issue for many organizations. To support organizations with this activity, authoritative bodies have published many different guidelines. Nevertheless, these guidelines show limitations in identification of the direct and indirect processes that have a major impact on climate change, which should be considered in GHG management. In this paper, a life cycle approach is used to identify the processes of an organization and its supply chain that have major impacts on climate change. The results show that this approach is compatible with the current ISO standards and that in the case study the greatest emissions come from the organization’s indirect processes.

Differences in wear between load and displacement control tested total knee replacements

Two identical sets of posterior cruciate retaining total knee replacements were tested for wear on one contemporary knee joint simulator according to the current ISO standards. The first set of implants was tested in load control mode (ISO 14243-1), while the second set was tested in displacement control mode (ISO 14243-3). The type of control mode alludes to the feedback signal of anterior–posterior and internal–external degrees of freedom. Resulting wear scars and rates between the different control mode tests were compared. Significant differences in wear rates were found: the wear rates in displacement control were approximately half of the wear rates in load control mode. This result was mirrored in the wear scars, which were significantly different in size on the medial plateau. Comparing wear rate with wear scar size (area) yielded a positive correlation. Analyzing the motion data of the two tests revealed similar ranges of movement in anterior–posterior translation and internal–external rotation, however the time-scale of the rotational movements differed between the two control types, explaining the differences in wear. This study demonstrated that substantial variability in wear outcome is possible depending on the type of control mode. Future revisions of testing directions should incorporate more implant specific test parameters to produce clinically relevant wear results.

The relationship between the minimum zone circle and the maximum inscribed circle and the minimum circumscribed circle

Following the minimum zone criterion set forth in the current ANSI and ISO standards, evaluation of roundness error is formulated as a non-differentiable unconstrained optimization problem and hard to handle. The maximum inscribed circle and minimum circumscribed circle are all easily solved by iterative comparisons, so the relationship between the minimum zone circle and maximum inscribed circle, minimum circumscribed circle is proposed to solve efficiently the minimum zone problem. Based on the known minimum zone circle, the maximum inscribed circle and minimum circumscribed circle can be easily determined. The relationship is implemented and validated with the data available in the literature.

Numerical modeling of sonic boom propagation from hypersonic aircraft

A numerical study of sonic boom propagation from hypersonic aircraft is performed including the effects of nonlinearity, atmospheric absorption and dispersion, and atmospheric stratification. A second-order split-step algorithm, which alternates application of nonlinearity in the time domain and complex absorption in the frequency domain, allows for a faster convergence of results with fewer range steps than with conventional first-order algorithms. Nonlinearity is calculated using the potential, the integral of the pressure, as proposed by Burgers and later applied to sonic booms by Hayes et al. This method, an alternative to Landau's law of equal areas, efficiently locates the shock position by selecting the maximum potential in multivalued regions. Definition of atmospheric absorption at high altitudes is important for modeling the propagation of sonic booms from hypersonic aircraft. Some aspects of an extended absorption model by Sutherland and Bass are adopted, therefore, which extend absorption predictions above the 20 km limit of the current ISO and ANSI standards. The study is completed using the meteorological conditions at two locations, Le Havre, France and Edwards Air Force Base, CA, USA, over the course of a year. [Work supported by European Union through ATLLAS AST5-CT-2006-030729, meteorological data provided by ECMWF.]

Measurement of sound power and absorption in reverberation chambers using energy density

Reverberation chamber measurements typically rely upon spatially averaged squared pressure for the calculation of sound absorption, sound power, and other acoustic values. While a reverberation chamber can provide an approximately diffuse sound field, variations in sound pressure consistently produce uncertainty in measurement results. This paper explores the benefits of using total energy density or squared particle velocity magnitude (kinetic energy density) instead of squared pressure (potential energy density) for sound absorption and sound power measurements. The approaches are based on methods outlined in current ISO standards. The standards require a sufficient number of source-receiver locations to obtain suitable measurement results. The total and kinetic energy densities exhibit greater spatial uniformity at most frequencies than potential energy density, thus requiring fewer source-receiver positions to produce effective results. Because the total energy density is typically the most uniform of the three quantities at low frequencies, its use could also impact the usable low-frequency ranges of reverberation chambers. In order to employ total and kinetic energy densities for sound absorption measurements, relevant energy-based impulse responses were developed as part of the work for the assessment of sound field decays.

Influence of surface finish and residual stresses on the ageing sensitivity of biomedical grade zirconia

We demonstrate in this paper the influence of surface finish on the ageing kinetics of biomedical grade zirconia. The critical influence of polishing has been systematically investigated by optical microscopy, atomic force microscopy and X-ray diffraction. The stress state around polishing scratches gives rise to preferential transformation in the zone of the induced scratches and consequently to accelerated ageing. The influence of residual stresses is analyzed semi-quantitatively by preparing samples with various surface finish, thus with various stress states. Rough polishing produces a compressive surface stress layer beneficial for the ageing resistance, while smooth polishing produces preferential transformation nucleation around scratches. When a thermal treatment of 2 h at 1200 °C is applied to relax the residual stresses, all the surfaces states exhibit the same sensitivity to ageing. These results demonstrate that roughness alone cannot be used for ensuring a long-term stability. The variation of ageing sensitivity is indeed related indirectly to the surface roughness via the induced surface stress state. The current ISO standards are not able to take these effects into account. Indeed, great variations in ageing kinetics were observed for samples with different surface states, although all well below the ISO requirements.

Effect of aperture size on irradiance of LED curing units

Objective: The aim of this study was to evaluate the light output from LED-curing units measured according to the current ISO standards. The effect of aperture size on irradiance was also evaluated. Method: The irradiance of light-curing units and the depths of cure of composites exposed to these units were determined using the methods outlined in ISO standards, ISO/TS10650 and ISO 4049, respectively. The irradiance measured through two different sized apertures was also measured. Results: The irradiance measured with an aperture was greater than that without an aperture. For each light-curing unit and material, there was a linear relationship between the depth of cure and the logarithm of the amount of exposure, which is defined as the product of the irradiance and irradiation time. The correlation coefficients of these linear relationships, using data obtained from the different units was only moderate when the irradiance was measured without an aperture. The correlations improved with decreasing aperture size. Significance: Since the irradiance is affected by the angular aperture of the light guide and the size of the mold for measuring depth of cure of resin in ISO 4049 is 4-mm diameter, the irradiance through a 4-mm aperture should be used in the determination of the relationship between depth of cure and light exposure.

A Review of Accelerated Test Methods for Predicting the Image Life of Digitally-Printed Photographs – Part II

This paper gives an overview of the various factors affecting the permanence of digitally-printed photographs.1 Accelerated test methods are discussed, with emphasis on light stability tests specified with past and current ANSI and ISO Standards, future ISO Standards, and the “de facto” test method standards now widely used in the imaging industry, such as the predictive “Display Permanence Rating” test method developed by Wilhelm Imaging Research and the predictive stability test methods employed by Eastman Kodak for evaluation of Kodak Ultima Picture Paper (ColorLast, 2003 type). Light stability data for representative products evaluated with these two “de facto” test methods are given, and the major factors that account for the large differences in outcomes are presented.The potentially large impact of reciprocity failures in highintensity accelerated light stability tests is illustrated with longterm test data for an inkjet paper printed with dye-based inks. The importance of the selection of the spectral power distribution of the illumination source employed for accelerated light stability tests is emphasized.